Sump well/ dry pit - when to drain?

[MostlyCanuck]

I have a 3' deep, 10" diameter, sump well installed by the shallow end (where the pool water is 3.5' deep).
It's generally bone dry but we've been getting a few days of constant rain and there's about 8" of water in there now.

At what point should I put a sump pump in to drain it? how much water is too much? I read one comment in the forum from a while ago suggesting no issues as long as water in well is at least 1 foot below pool water level but this is my case would mean the 3' deep well would have more than 2 feet of water in it which seems like a lot...

(my pool is 8' deep so 8" of water by the shallow end means there's lots of water surrounding the rest of the walls as you move towards the deep end)

 

[1Sammy]

Not sure if there is a nice way to say this but, you sump is useless. It would not even be good enough if all of your pool was 3.5' deep, sorry. Not knowing your backfill material etc i would say you have soft corners in the deep end and from bottom to sides ? Anyway, to answer your question as to amount of water in that set up. You want zero.

 

[MostlyCanuck]

Not sure if there is a nice way to say this but, you sump is useless. It would not even be good enough if all of your pool was 3.5' deep, sorry. Not knowing your backfill material etc i would say you have soft corners in the deep end and from bottom to sides ? Anyway, to answer your question as to amount of water in that set up. You want zero.

while i appreciate the candor, that doesnt make me feel super well....!

i was under the impression that it was pretty standard for vinyl pools to have the sump pit by the shallow end with shallow-end depth (vs fiberglass pools which I understand have it by the deep end and it goes way deeper)

why is my sump pit useless?!

the backfill right around the steel walls was gravel - if that helps.

 

[1Sammy]

Water will sink to the lowest it can especially in gravel. 3.5 feet is lower the 3 feet. 8 feet is much lower then a 3 foot deep sump. So it just makes sense that the gravel will need to be filled before any water will show in your 3 foot sump. Water of course will also sink into clay if you have it, slow, but it will. So for any water to be up in the 3 foot area all the ground under that depth will need to be full first. Now there will be sum water caught on the way down, but only in the area of the sump.

 

[MostlyCanuck]

Thanks for pointing that out. Makes sense.

Do you think there's value in using an auger or something like that to dig down deeper and install a longer PVC tube - ie make that sump pit deeper? ( I'm not even sure if it's feasible/pragmatic without damaging the pool walls or the stone deck around it to be honest... But if it's doable and useful I could look into doing that)

 

[1Sammy]

For sure useful. I go 1 foot lower then the lowest depth of the pool. Even without piping or a crushed stone path to the sump, water will in time make its own "underground river" to it and will more useful then nothing. Keep a pump with a float switch in there full time so it will kick in and out on its own. We can not use a back flow down at the pump as the water in the line will freeze up at the top. You will get water dropping back that is in the line but never enough that i have ever had issues with.